Digital Rights Management (DRM) refers to technologies that manage access to and usage of digital content such as songs and movies. DRM associated with some piece of digital content often requires a device (e.g., a personal computer or a digital audio player) to obtain a license before being allowed to consume the digital content. Typically, this license not only allows the device to consume the digital content, but also specifies rights or restrictions by which the device may do so. The license may, for instance, allow the device to play the digital content but not copy the digital content to a second device.
Traditional DRM systems employ a file format that specifically targets audio or video content. Audio and video content, however, generally consists of a linear format. A song, for instance, typically follows a timeline and consists of an ordered set of samplings. While traditional DRM systems do well to manage these linear data formats, these systems typically can not efficiently manage non-linear data types.
In addition, traditional DRM systems typically protect a single and self-contained digital work, such as a song or a movie. As such, traditional DRM systems typically specify a single policy for this single digital work. These traditional systems, however, generally fail to protect to a collection of data or multiple collections of data, each of which may consist of a multitude of data types. Traditional DRM systems therefore do not allow for efficient grouping and flexible protection of one or more collections of various pieces of data.